1. Field of the Invention
The present invention relates generally to an apparatus and method for generating a frame sync word and verifying the frame sync word in a CDMA (Code Division Multiple Access) communication system, and in particular, to an apparatus and method for generating a frame sync word and verifying the frame sync word in an asynchronous CDMA (W-CDMA) communication system.
2. Description of the Related Art
As the third-generation mobile communication is under standardization, efforts are expended toward the integration of mobile communication systems around the world.
Especially, harmonization of the North America CDMA 2000 and the European W-CDMA is accelerated. In the course, the probability is increased that a chip rate of 3.84 Mcps will be used commonly in a W-CDMA communication system and asynchronous CDMA (referred to as CDMA 2000, hereinafter) communication system which have used their different chip rates of 3.6864 Mcps. Therefore, the W-CDMA system should be reconfigured in such a way that it can operate at a chip rate reduced to a 15/16 (3.84 cps/4.096 cps) of the original chip rate of 4.096 Mcps. The best way of redesigning the conventional W-CDMA system without any modification to its slot structure is to reduce 16 slots per frame to 15 slots per frame.
The change in the number of slots per frame for harmonization between CDMA 2000 and W-CDMA is accompanied by a design modification to a pilot sync word pattern for use in frame synchronization verification.
The W-CDMA radio communication standards under development in the 3GPP (3rd Generation Partnership Project) as of May 1999, one of conventional W-CDMA communication system technologies, involves frame synchronization verification using a sync word. The sync word in the conventional technology is designed on the assumption that one frame has 16 slots. Now, a new sync word fit for a 15 slots per frame structure is under development. As one frame has 15 slots, a frame sync word generating apparatus should be redesigned in the W-CDMA communication system. With the new frame structure, a conventional synchronization verification method based on the 16 slot-per-frame structure is not applicable to the W-CDMA system. Hence, a new synchronization verification method should be explored adaptively to the changed 15 slots-per-frame structure.